Features (e.g., routes) and pitches (e.g., spacing between features) of IC designs continue to decrease in size. In order to support such features and pitches, many IC designs form features utilizing DPT. FIG. 1 illustrates an exemplary DPT process. As shown, an overall route pattern 101 is generated from a partial route pattern 101a formed by a first mask and a partial route pattern 101b formed by a second mask. By using two separate masks, the pitch 103 between features using DPT may be less (e.g., half) than a pitch using a single mask, such as pitch 103a and pitch 103b. 
IC designs utilizing DPT, however, require zero odd cycle for the designs to be decomposable by the separate masks. FIG. 2 illustrates an exemplary even cycle that is decomposable utilizing DPT, and FIG. 3A illustrates an exemplary odd cycle that is not decomposable utilizing DPT.
Adverting to FIG. 2, the target pattern 201 has features 203, 205, 207, and 209 which have a pitch 211 (e.g., pitch 211a, 211b, 211c, and 211d), between each vertical or horizontal pair, that a single mask cannot decompose. However, an even number (e.g., two) of masks may decompose the target pattern 201. Specifically, a first mask may decompose a partial pattern 201a having features 203 and 209 because a pitch 213a (along the diagonal) separating the features is greater than a minimum pitch for a single mask. Likewise, a second mask may decompose a partial pattern 201b having features 205 and 207 because a pitch 213b (along another diagonal) separating the features is also greater than a minimum pitch for a single mask. Thus, although nearby features have a pitch 211 requiring separate masks to decompose the features 203 through 209, the target pattern 201 is nonetheless decomposable using DPT.
Adverting to FIG. 3A, the target pattern 301 is not decomposable using DPT. The features 303, 305, and 307 of target pattern 301 have a pitch 309 (e.g., 309a, 309b, and 309c) for each pair that a single mask cannot decompose. Specifically, a mask may only decompose one of features 303 through 307 because pitch 309 separating the features is less than a minimum pitch for a single mask. Thus, an odd (e.g., three) number of masks are required to decompose the target pattern 301, rendering DPT unable to decompose the target pattern 301.
To avoid odd cycles in IC designs utilizing DPT technology, routing jogs are highly discouraged since they often lead to odd cycles. For example, as illustrated in FIG. 3B, routing jog 311 creates odd cycle 313. However, such a restriction degrades routing efficiency and may lead to the consumption of additional chip area. Thus, traditional designs utilizing DPT frequently suffer from poor routing efficiency.
One solution to the poor routing efficiency is the use of an additional route pattern in the IC design to perform the jogging function. However this additional route pattern is very difficult to implement using traditional methods because IC designs must utilize a stitch-aware routing tool for connecting the two route patterns to avoid odd cycles.
A need therefore exists for a methodology enabling the jogging function to improve routing efficiency without the need for difficult to implement tools such as stitch-aware routing tools.